In mobile communication, a variety of different frequency bands is used for transmission and reception of radio frequency (RF) signals. Accordingly, a RF transceiver or a RF transmitter of a mobile communications device must be able to operate within these frequency bands, which places high demands to the RF transceiver or RF transmitter. For example, in 2014, a transceiver of a mobile communications device had to operate with frequencies between 704 MHz and 2690 MHz. For example, frequency bands 1, 2, 3, 5, 7, 8, 9, 11, 18, 19, 20, 21, 25, 26 and 28 used for Frequency Division Duplex (FDD) communication within the Long Term Evolution (LTE) system, frequency bands 38, 39, 40 and 41 used for Time Division Duplex (TDD) communication within the LTE system, frequency bands 34 and 39 used for Time Division Synchronous Code Division Multiple Access (TD-SCDMA) communication within the Universal Mobile Telecommunications System (UMTS) and frequency bands 1 to 6, 8, 9 and 19 used for Wideband Code Division Multiple Access (WCDMA) communication within UMTS had to be supported. Hence, the transceiver needs to cover a relative bandwidth of 117%. For example, in 2015, additional frequency bands 30, 42, 43, 10, 23, 24, 33, 35, 36, 37, 12, 13, 14, 17, 27, 44 and TV600 may be supported, so that a transceiver of a mobile communications device may be able to operate with frequencies between 570 MHz and 3800 MHz. Hence, the transceiver needs to cover a relative bandwidth of 148%. In future years, a further broadening of the frequency spectrum to be supported by a transceiver of a mobile communications device is expected. For example, a lower limit of the frequency spectrum may be shifted to 450 Mhz. Relative bandwidths of 150% and more may be expected.
Furthermore, RF transceivers may support carrier aggregation, i.e., the aggregation of two or more component carriers.
With available transceiver technology, an increasing number of transmission output stages including, e.g., Digital-to-Analog Converters (DAC) and inductance matching networks for RF applications, is necessary in a mobile communications device to cope with the above demands. Hence, an improved transmission stage may be desired.